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junglejustice
Verde
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Location: Granolaville, WA

Catastrophic Wiring Harness Melt-Down; Long...

Post by junglejustice »

Well, as some of you already know, while Ron Simons was visiting us here for the National Alfa "Potlatch" convention, my street Verde (running Standard GoTech) experienced a complete wiring melt-down...

This right in the freakin' middle of the Friday time trials sessions at Pacific Raceways! My main harness caught fire and melted all of the way from the fuse-box under the dash to the key-ignition to the firewall and in to the engine-bay side...

In a valiant effort we ripped the entire dash out, jumped wires and bypassed the ignition with a hot-wire solution straight out of a bad episode of cops. The Icelander - Jon - was able to apply his skills from a miss-spent youth to get us going again and basically hotwired the car!

We ripped the entire dash out, rigged up some by-pass wires and I was able to go out for part of the afternoon before it all went to hell. I mean, I finally fried everything! (Even the GoTech harness...) Wild thing is that even after some more rigging and bypassing and with melted crap everywhere, the GoTech ECU DID NOT GET DAMAGED! Turned out that we were running it un-fused (pretty stupid, I know) too...

I even drove it home with no dash, no lights and smoking wires hanging everywhere...

Any way, it took days down at Group 2 to rip most of the OEM harness out behind the dash and replace all kinds of wiring. Luckily I had an extra GoTech harness here too so we were able to completely redo it. In the process I was now also able to COMPLETELY remove the stock L-Jet harness.

For those who don't know - YOU TAKE IT ALL OUT!!! I mean the whole thing! Nice... I removed the ECU finally (although that was not working anymore) I was still powering the idle-control valve and I am sure that there was some interference there - (it only needs power to work, not ECU communication...) I removed the temp gauge wires and warning light wires from the front of the thermostat housing and just ran fresh wires to it.

I ran a new fuel pump relay over to the correct points on the 9-pin connector on the passenger side by the firewall, removed the double relays etc. We also took the time to hook up a TP100 ignition module (which kind of serves the same function as the "fly-back board on the MS conversions) to allow you to run low impedance injectors...

ANOTHER CLARIFICATION HERE:
It was my understanding that you "can't" run low impedance injectors with the GoTech Standard... Well, my car ran OK with it (with LI injectors...) Turns out that the issue is that it WILL run, but "not properly" unless you use the ignition module or install high impedance injectors. Now they work well....

So, by moving the jumper to the center set of pins you now run TWO drivers and you run the injectors via the TP100 which powers them properly. The net result was that my old map went WAY rich... Actually, the map was the same, but the injectors were now opening and closing faster etc so I had to trim my map WAY back all across the board and the ECU runs cooler too!

ANOTHER POINT OF NOTE:
Since I now required some re-mapping, I dared to go after another mystery piece: the "Invert trigger" function in the F5 setup screen. If yours is set to 0 and you set it to 1, or if it is set to 1 and you move it to 0 (zero) you effectively move the chopper tip inside of the dizzy on the 6-blade chopper that you fire from and avoid having to "jump" the spark too far to the correct plug wire...

So, if in your early attempts to start your car off of GT for the first time, you ended up with the distributor rotated left (or, counter-clockwise) - advanced - so far forward to where the plug wires coming out of the dizzy cap are hitting the air/vapor separator on the passenger side valve cover, then you need to do this!!!!!! You can probably see a black "burn-line" forming on the inside of the cap from the spark "jumping" so far..."

Very simply; the car runs fine now and you don't want to mess with the map? - Fine. Throw a timing light on it and check your physical crank timing at a set RPM - say 1000 rpm idle. (Mark your dizzy position on the housing first if it will make you feel safer...) then, set the "Invert Trigger" setting inside of the F5 setup screen to the opposite of what it is now. Mine was set at 0 and I set it to 1. Move the dizzy clockwise about 1 inch at the base. Start the car and use the timing light to set the dizzy back to where your crank now shows the exact same advance as before. Your map didn't move, the wires are not pressed up against the A/V separator and the spark doesn't have to jump so far.

Car runs much better now. Looks good all put together again. Engine bay is more cleaned up.
...to Alfa, or not to Alfa? That is the question...
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Andrew.b
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Re: Catastrophic Wiring Harness Melt-Down; Long...

Post by Andrew.b »

We also took the time to hook up a TP100 ignition module (which kind of serves the same function as the "fly-back board on the MS conversions) to allow you to run low impedance injectors...

ANOTHER CLARIFICATION HERE:
It was my understanding that you "can't" run low impedance injectors with the GoTech Standard... Well, my car ran OK with it (with LI injectors...) Turns out that the issue is that it WILL run, but "not properly" unless you use the ignition module or install high impedance injectors. Now they work well....

So, by moving the jumper to the center set of pins you now run TWO drivers and you run the injectors via the TP100 which powers them properly. The net result was that my old map went WAY rich... Actually, the map was the same, but the injectors were now opening and closing faster etc so I had to trim my map WAY back all across the board and the ECU runs cooler too!

[/quote]

JJ,

I think you may have this a little mixed up - or have discovered a new way around this problem :)

Yes the car will run with low impedence injectors, as you have proved, but they will run incorrectly, as there is not enough 'juice' in the injector output - pin.3 and pin.11 (brown/red 1.5mm)

Although it seems there are 2 seperate driver outputs for the injectors, there is only one. The two 1.5mm brown/red outputs become one inside the box, and are fed by a single injector driver.

To enable the use of 6 low impedence injectors you must split them into pairs of 3.

One pair is driven by the (brown/red 1.5mm) pin.3+11 injector output

The second pair is driven by the (blue/white 1.5mm) pin.2 - this is the optional output that is used for driving the coil, by internal direct fire from the ecu.

This is why you have to set the box to external fire, and use a TP100 ignition module to fire the coil. (this module is standard on a 75, and is next to the coil)

The TP100 is an ignition module for powering the coil, and has no control over the injectors.

So if you have a 75 running gotech, with standard injectors, you must go with external fire with a tp100 ignition module (the black plug next to the coil) and rewire the injectors to split between brown/red for 3, and blue/white for the other 3.

you will loose the option of fuel pump control, shift light, vvt ect.

Hope this makes sense! :)

have a look here
http://www.gotech.co.za/forum/viewtopic.php?t=99
Andrew b
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SamW
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Post by SamW »

JJ,

Sorry to hear about the harness fire, never a good thing. Glad you got it back going. Did you use another Milano Harness or did you make your own? I am running the Alfa Ign module on my Verde, seems to work pretty good.
MerrilGordon
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Post by MerrilGordon »

Get this everyone, JJ still managed to record a lap of 1:51.78 in class B. Not sure if that was with or without dash & wiring :-)

That compares with Michael Harris driving his GTV6 in class C at 1:49.72
Chris Benny's Milano class C at 1:52.35
Dave Bibby's GTV6 class D at 1:52.94
Thomas Moll's Alfetta Class D at 1:54.48 (fast combinaton)
And me in class D at 1:55.59 (Did they miss a flying lap of mine ;-)

Also of note was Portland Oregon's Randy Johnson in his class A electric blue Alfetta with a 24v engine and heavily worked over chassis did a 1:43.19. He gets lots of track time in as well.

Lastly there was a 2004 M3 that ran a 1:44.40, not sure of Mitch Hobbs driving experience.
And Jay Maveety's 86 BMW 325 running a 1:51.16. I think his car had numerous modifications.

Merril
82 GTV6 3.0
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4agedub
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Post by 4agedub »

sorry to hear about your bad wiring meltdown... You're lucky that the ecu was not damaged. what did u do to get the cop's attention? here in RSA they can also be a pain in the @rse
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Tel: +2711 3978197
Email: louis@gotech.co.za
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